The invention concerns a medical warming apparatus for infusion, transfusion, and/or cleansing solutions with a regulatable and/or controllable heating device, acting on a conduit for the fluids, which warms a cylindrical heat exchanging body exhibiting a groove on the outer side for the insertion of the conduit through which the fluid is flowing and forming windings w with heat transfer length l per winding w.
An apparatus of this kind has become known in the art through publication EP 0 181 447 B1.
The apparatuses known in the art for the warming of infusions or transfusions having a cylindrically shaped heat exchanging body, exhibit a groove on the outer side, running in a screw-like fashion, for insertion of a conduit through which the fluid to be warmed flows. The heat exchanging bodies contained within apparatus housings are manufactured from a good heat conducting material in order to warm the fluid flowing in the conduit by contact heat transfer.
In the known apparatus in accordance with EP 0 181 447 B1, the heat exchanging body is directed vertically and the conduit arranged in the outer region of the heat exchanging body is covered with a heat protecting cuff. Using a groove shape which is adapted to the conduit and by covering the conduit running in the groove, it is possible to minimize the radiative heat losses and achieve, to a large extent, a uniform warming of the fluid flowing in the conduit. In another apparatus which is also part of prior art and which has become known through EP 0 444 011 A1 the heat exchanging body is configured as a horizontally directed straight circular cylinder and the conduit guiding the fluid is pressed into a groove running on the outer side of the circular cylinder. The groove is configured in such a fashion that, on the one hand, it is substantially deeper than the outer diameter of the conduit to be placed into the groove and the groove bottom is displaced relative to the groove opening. The groove exhibits side walls running from the groove bottom to the groove opening which present a narrowed region to the conduit to be placed into the groove along the entire depth of the groove.
In addition to these instruments an additional apparatus produced by the company Dideco (see EP 0 181 447 B1 column 1 lines 10 ff) is also known in the art which likewise exhibits a horizontally directed heat exchanging body configured as a straight circular cylinder.
In the apparatuses known in the art the heat transfer length to the conduit guiding the liquid is limited by the number of grooved loops on the heat exchanging body. If, as known in the art, the individual groove loops are arranged in closer proximity to each other, it is thereby only possible to lengthen the heat exchanging length by a limited amount and the ease use of the apparatus is reduced.
Conventional heat transfer lengths with cylindrical heat exchanging bodies are up to approximately 37 cm per loop (winding).
It is also necessary to take into account, excluding the apparatus in accordance with EP 0 181 447 B1, that, in addition to the limited heat transfer length, an uncontrolled convective heat loss also occurs in the outer region of the conventional heat exchanging cylinder which does not improve the efficiency of the effective warming of the fluid. Should the grooves be configured very deeply in the conventional heat exchanging cylinder, there is the additional danger that the struts between the grooves assume the function of cooling ribs over a large region to cancel out the advantages associated with the corresponding groove shape. Likewise with the conventional deeply configured groove cross sectional shapes it is not possible to easily check whether or not the conduits inserted into the groove seat tightly on the groove bottom. If this is not the case a strong reduction in heat transfer results.
Therefore the underlying problem of the invention is to further improve the conventional heat exchanging cylinder in such a fashion that the radiative losses to the environment are reduced.